Detection device for indicating short circuits in electrolytic cells

ABSTRACT

An electrical unit for sensing a steady magnetic field intensity produced by the flow of direct current is mounted in a carriage a fixed distance from the running surface of the carriage and is electrically connected in circuit with indicating means, which may be visual means, such as a light, or an audible alarm or both, energized in response to the sensing of a magnetic field of intensity greater than is produced by electrical current flow of up to a predetermined normal maximum amperage. The carriage is preferably of sled formation adapted to be pushed or pulled across a multitude of electrode suspension bars arranged in series along electrolytic cells in an electrolytic tank house, which bars serve to conduct current to the electrodes. The sensing unit is advantageously a magnetodiode, but may be any one of a number of possible alternatives, e.g. reed relays, electrically connected in suitable control circuitry.

Templeton et al.

[ 1 Feb. 12, 1974 DETECTION DEVICE FOR INDICATING SHORT CIRCUITS INELECTROLYTIC CELLS [75] Inventors: Frederick E. Templeton; William M.

Tuddenham; Veloy H. Butterfield, ,Ir.; Barton F..Shipley, all of SaltLake City, Utah [73] Assignee: Kennecott Copper Corporation,

New York, NY.

[22] Filed: Jan. 5, 1972 [2]] Appl. No.: 215,508

[52] US. Cl. 340/253 A, 324/43 R [51] Int. Cl. G081) 21/00 [58] Field ofSearch 340/253 A, 253 R, 249, 253 F,

340/248; 324/43 R, 52, 37 R, 61 P, 54

3,559,199 l/l97l Schafer 340/253 A Primary Examiner-.lohn W. CaldwellAssistant Examiner-Daniel Myer Attorney, Agent, or Firm Philip A.Mallinckrodt [57] ABSTRACT An electrical unit for sensing a steadymagnetic field intensity produced by the flow of direct current ismounted in a carriage a fixed distance from the running surface of thecarriage and is electrically connected in circuit with indicating means,which may be visual means, such as a light, or an audible alarm or both,energized in response to the sensing of a magnetic field of intensitygreater than is produced by electrical current flow of up to apredetermined normal maximum amperage. The carriage is preferably ofsled formation adapted to be pushed or pulled across a multitude ofelectrode suspension bars arranged in series along electrolytic cells inan electrolytic tank house, which bars serve to conduct current to theelectrodes. The sensing unit is advantageously a magnetodiode, but maybe any one of a number of possible alternatives, e.g. reed relays,electrically connected in suitable control circuitry.

12 Claims, 5 Drawing Figures I PATENTEDFEB 1 2mm sum 1 or z DETECTIONDEVICE FOR INDICATING SHORT CIRCUITS IN ELECTROLYTIC CELLS BACKGROUND OFTHE INVENTION number in so-called tank houses for a variety of purposes,among them being the electrorefining or the electrowinning of variousmetals, such as copper. It has been customary to test for the existenceof electrical short circuits between anode and cathode electrodes ofpairs of such electrodes in such electrolytic cells by having a workmanwalk back and forth on walk-ways provided above and along the cellswhile holding the compass-carrying lower end of a probe immediatelyabove the series of conductor bars that serve to suspend the electrodesin liquid electrolyte within the cell tanks. Excessive displacement ofthe compass needle is indicative of an electrical short circuit, but itis difficult to.make any exact determination because of the tendency forthe lower end of the probe to deviate from a constant level and becauseproper interpretation of the compassreading depends upon the skill'ofthe workman using the probe.

SUMMARY OF THE INVENTION In accordance with the present invention,individual vagaries are eliminated andhighly accurate indications ofelectrical short circuit conditions are given positively by mounting asensing unit for steady magnetic field intensity in a carriage,preferably of sled formation, at a fixed distance above the runningsurface of the carriage, and by electrically connecting such unit incircuit with one or more indicators of excessive field intensity, e.g. alight, an audible alarm, etc. The carriage may be provided with anelongate handle enabling a workman to use it as he would the usualprobe, except-for the important difference that the carriage spans anumber of the suspension bars at a time, riding upon them to maintainthe sensing unit at a fixed level relative thereto. The electricalcircuitry and power supply for the sensing unit may be carried by theworkman on a belt around his waist, or may be built into the carriage,depending upon the type of sensing unit employed and otherconsiderations. It is preferred and a feature of the invention toutilize either a commercially available magnetodiode as the sensing unitor a special arrangement of reed relays.

THE DRAWINGS Specific embodiments constituting the best mode presentlycontemplated for carrying out the invention are illustrated in theaccompanying drawings, in which:

FIG. 1 is a fragmentary pictorial view, somewhat schematic in character,showing a portion of an electrolytic cell and suspended cathodeelectrodes as well as'a probe in accordance with-the invention, theprobe having a sled-type carriage with a magnetodiode sensing unitconnected into electrical circuitry carried by a waist-encircling belt;

FIG. 2, a plan view of the carriage, showing the sensing unit and fluxconcentrator therefor by broken lines and including the probe handleonly fragmentarily;

FIG. 3, a side elevation of the carriage as shown in FIG. 2, butincluding the upper end portion of the probe handle and an electricalcord provided with a plug-in facility for the belt-carried items;

FIG. 4, a wiring diagram of electrical circuitry advantageously utilizedfor the device of FIGS. 1-3; and

FIG. 5, a wiring diagram of electrical circuitry advantageously utilizedwhen reed relays are employed for the sensing unit of the device.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS In the formillustrated in FIGS. 1-4, the device of the invention comprises acarriage 10 of sled formation including a runner 11 and housing 12 for asensing unit 13, FIG. 3, and flux concentrators 14 located at oppositesides of unit 13, as indicated. Standards 15, respectively, fixed to thetop of runner 11 at opposite sides of housing 12 serve as mounts for theclevised lower end 16a of an elongate hollow handle 16, a pivot pin 17securing the clevis 16a in the standards so handle 16 can be swungtoward one end or the other of the runner for change of direction ofmovement without bodily turning the carriage around. For this purpose,runner 11 has both of its ends upturned as shown.

Electrical conductors encased in a lower cord 18 enter the lower end ofhandle 16 from electrical connection with sensing unit 13, which in thisinstance is a magnetodiode, continue upwardly through the interior ofhandle 16, and emerge in an upper cord 19 for electrical connection, asby a plug 20, with electrical circuitry in a box 21, FIG. 1, carried ina pouch 22 attached to a belt 23 adapted to encircle the waist of aworkman in an electrolytic tankhouse. Power is supplied to the circuitryin box 21 and to sensing unit 13 by an electrical storage battery 24carried in a pouch 25 also attached to belt 23.

Sensing unit 13 is secured in fixed position within housing 12 by anysuitable means at a predetermined distance, see d, FIG. 3, from therunning surface of the carriage, i.e. from the underside 11a of runner11. Thus, when a workman wearing belt 23 and pushing carriage 10 acrossa multitude of cathode suspension bars 26, FIG. 1, arranged in seriesalong an electrolytic cell 27 in an electrolytic tankhouse, slidesrunner 11 along the series in the sequential traversal of the bars 26,sensing unit 13 remains constantly at a predetermined fixed level abovesuch bars 26.

If reed relays or some other electrical alternatives are employed forthe sensing unit, the same important consideration of mounting them at afixed predetermined distance above the underside 11a of runner 11applies.

The purpose of the sensing unit is to measure intensity of the magneticfield surrounding each suspension bar 26 as the device is pushed orpulled along the series of bars above a cell 27 in the electrolytictankhouse. Intensity of magnetic field is directly proportional to theamperage of the electrical current flowing through the bars. Thus, whenthere is an electrical short circuit for one reason or another thatshould be corrected, increase in intensity of magnetic field above anormal maximum results from the increase in current flow due to theshort circuit conditions. For example, with normal current within arange of somewhat below and somewhat above 400 amperes, a short circuitcondition could result in current ranging from about 600 to 1,000 ormore amperes, depending upon the severity of the short. Magnetic fieldintensity would be a direct measure of this highly undesirable increasedcurrent flow, and the device of the invention is designed to indicatesuch an undesirable condition by means of a visual or an audible signalor both.

As illustrated, indicator lights 27 and 28, FIG. 2, for normal currentflow and for excessive current flow, respectively, serve to providevisual signals, and an alarm (see Sonalert 31, FIG. 4) is eitherassociated with the electrical circuitry in box 21 or is positionedalong with the sensing device in housing 12 to provide an audible signalwarning of excessive current flow.

Considering now the electrical nature and operation of the device ofFIGS. 1-4, it is noted that a magnetodiode is sensitive to changes inmagnetic field intensity from the standpoint of impedance and iscommercially obtainable from Sony Company, Tokyo, Japan. Such a diode isdesignated 13 in the wiring diagram of FIG. 4.

In the specific circuitry shown in FIG. 4, battery 24 supplies directcurrent to a DC to DC converter 29 whose higher voltage is used to powerseveral integrated circuits. Q is a voltage regulator'in the form of anintegrated circuit, e.g. manufactured by National Semi-Conductor Co.under the designation LM305. It limits the +15 output from converter 29to +6 volts. Capacitors C4 and C5 are used for stabilization. ResistanceR19 limits the output current, and resistances R20, R21, and R57 adjustthe output voltage to +6 volts. Resistance R54 adjusts the unregulatedB+ voltage applied to a voltsensor 30, which may be a commerciallyavailable unit designated 552 by its manufacturer, California ElectronicManufacturing Co., Inc. It similarly adjusts the voltage applied toindicator lights 27 and 28.

Six volts of regulated direct current are applied across themagnetodiode 13. The output voltage of such magnetodiode varies in theneighberhood of +3 volts, depending upon the strength and direction ofthe magnetic field caused by the current in the respective suspensionbars 26. This output signal voltage is fed through a high inputimpedance, voltage follower Q1 with near unity gain.

Resistances R8, R9, and R50 make up a voltage divider enabling selectionof a regulated direct current at approximately +3 volts, which is fedthrough a similar voltage follower Q2. The voltage followers Q1 and Q2are integrated circuits, e.g. National Semi-Conductor Co. LM302.Resistances R1 and R2 stabilize the inputs of Q1 and Q2. Resistance R51is adjusted to compensate for input offset voltage between Q1 and Q2.

Voltage followers Q1 and Q2 both feed a circuit difference amplifier Q3,e.g. a National Semi-Conductor Co. LM30 l A. Amplifier Q3 has a voltagegain of thirty in this instance, which is set by resistances R3, R4, R5,and R6. Resistances R7, R22, R55 and capacitor C1 are used forstabilization and adjustment of input offset voltage. Resistance R50 isadjusted until the output voltage of amplifier Q3, as measured at testpoint 2J3, is zero when no magnetic field is present at magnetodiode 13.Resistance R53 adjusts the output voltage of amplifier Q3, which is fedto the input of voltsensor 30. The output voltage of amplifier Q3 variesin direct proportion to the magnitude of the magnetic field sensed bymagnetodiode 13. The magnetic field strength varies directly with themagnitude of the current in the respective suspension bars 26 suchcurrent being DC.

Voltsensor 30 is a dual setpoint, dual output, voltage comparator. Thesetpoints are determined by applying regulated voltages, derived byresistances R58, R59, R60, to manufacturer-designated terminals 7 and 9of voltsensor 30 for low and high setpoints, respectively. When theinput voltage to terminal 8 is less than the voltage to terminal 7, anoutput voltage is present at terminal 1. When the input voltage toterminal 8 is greater than the voltage to terminal 9, output voltageappears at terminal 3. When the input voltage is between the voltagesset on terminals 7 and 9, neither terminal 1 nor 3 is energized.

Resistance R58 is adjusted to a predetermined lower limit of suspensionbar current regarded as normal. Switch 251 selects resistance R59 orR60, either of which determines the upper limit of suspension barcurrent regarded as normal." This allows calibrating the instrument fortwo short circuit current levels. Suspension bar current greater thanthe selected normal level energizes terminal 3, which causes shortcircuit indicator light 28 to go on and also activates an audio alarm31, e.g. a Sonalert SC628.

A NOR logic circuit, comprising transistors Q8 and Q9 and resistancesR14, R15, R16, R17, and R18, energizes the normal indicator light 27whenever both terminals 1 and 3 are energized."This occurs when theinput voltage to terminal 8 is in the normal voltage range as set atterminals 7 and 9.

As previously mentioned, magnetodiode 13 is advantageously surrounded bya flux concentrator 14, that may be machined from a high permeability,nickel-iron alloy, e.g. one produced by Carpenter Technology Corp.,Philadelphia, Penn., as 49 FM CG Unannealed. This magnetically softmetal is approximately 50 percent iron and 50 percent nickel andexhibits very low magnetic retentivity. As indicated, it is preferablymachined into two conical pieces, which concentrate the magnetic fluxlines for passage through the magnetodiode, thereby providing magneticamplification.

The materials used for the carriage 10 should be corrosion resistant andmagnetically neutral, e.g. polyvinylchloride plastic and non-magneticstainless steel. Where aluminum is used, it is preferred that it becoated with an epoxy paint to prevent corrosion. Magnetodiode 13 andflux cncentrator 14 are preferably encapsulated in an acid resistant,electronic potting compound.

Although the described circuitry makes no provision for indicating lowerthan normal current flow between electrode pairs, this is oftendesirable and can be provided for in a generally similar manner whichwill be apparent from the foregoing.

Other sensing means than a magnetodiode can be utilized with appropriatecircuitry. Thus, as previously indicated, reed relays can be employed.Preferred circuitry providing both high and low current levelindications is illustrated in FIG. 5. In this arrangement, the reedrelays 32 and 33 and all circuit components are conveniently placed inhousing 12, FIG. 3, and protectively encapsulated therein by an elasticpotting material to reduce sensitivity to physical shocks duringoperation. Since no electrical conductors need pass through the hollowhandle 16, such handle is conveniently used to contain a battery powersupply 35 preferably yielding a voltage of between 16 and 22 volts.

used to set the bias on reed relays 32 and 33, respectively, thusdetermining the set points. Relay 32 is for low level current; relay 33is for high level current. If more levels are desired, a reed relay willhave to be added for each level.

Resistances R62 and R63 are connected in series with reed relays 32 and33 to narrow the magnetic field strength ranges required to operate andto release these relays.

Resistances R64 and R65 are provided to limit the current supplied tothe base of transistors Q and Q11, respectively. As voltage is appliedto R64 and R65, transisters Q10 and Q11 will switch on and will shortout resistances R62 and R63. As these resistances are turned on and off,the bias on reed relays 32 and 33 will change. For example, with a lowerthan normal magnetic field, voltage from batteries 35 is supplied to alow current indicator through reed relay 32 as well as to R64, whichturns on transistor Q10 and shorts out resistance R62. Reed relay 32 isthus connected across the total voltage being supplied through R10.

Indicator light 27 may in this instance be used as the low currentindicator, while indicator light 28 and audio alarm 31 may be used asthe high current indicator alerting to a short circuit condition.

When the magnetic field is increased to the point that reed relay 32 isactuated, the voltage is removed from resistance R64 and thus fromtransistor Q10. Resistance R62 is then in series with reed relay 32.Accordingly, the voltage drop across such relay is decreased. The valueof resistance R62 is chosen so the voltage across reed relay 32 plus themagnetic field is enough to hold such relay in an actuated position, yetsuch that a slight drop in the magnetic field strength will release therelay.

Resistance R65, transistor Q11, and resistance R63 have a similar effecton reed relay 32 when intensity of the magnetic field increases beyond apredetermined maximum, thereby energizing signal light 28 and alarm 31.All the electronic components with the reed relay sensors can be mountedin the sled with the batteries located in the handle.

The reed relays may be of any suitable type, for example those soldcommercially by Electronic Applications Co.

Whereas this invention is here illustrated and described with respect tocertain preferred forms thereof, it is to be understood that manyvariations are possible without departing from the inventive conceptsparticularly pointed out in the claims.

We claim:

1. A detection device for indicating short circuits in electrolyticcells, comprising a carriage having a running surface adapted to seatupon and travel across a series of electrode suspension bars conductingelectrical current to electrode pairs in an electrolytic cell; a sensingunit responsive to steady magnetic fields surrounding the respectivesuspension bars as produced by direct current flow through saidsuspension bars, said sensing unit being secured in said carriage at afixed level above said running surface thereof; and electrical controlcircuitry with which said sensing unit is electrically connected, saidcircuitry including signaling means and calibrating means and beingarranged to actuate said signaling means when the intensity of magneticfield to which said sensing unit is exposed exceeds a predeterminedlevel established by said calibrating means.

2. A detection device in accordance with claim 1, wherein the carriageis of sled runner formation.

3. A detection device in accordance with claim 1, wherein the sensingunit is a magnetodiode.

4. A detection device in accordance with claim 3, wherein fluxconcentrator means are associated with the magnetodiode.

5. A detection device in accordance with claim 4, wherein the fluxconcentrator means comprise a pair of flux concentrators at oppositesides, respectively, of the magnetodiode, each tapering toward themagnetodiode.

6. A detection device in accordance with claim 1, wherein the sensingunit comprises reed relay means.

7. A detection device in accordance with claim 6, wherein there are atleast vtwo reed relays, the control circuitry, including respectiveresistances arranged to bias said relays so they will be actuated atrespective predetermined levels of magnetic field intensity.

8. A detection device in accordance with claim 1, wherein the signalingmeans includes a set of two electric lights mounted on the carriage, andthe control circuitry is arranged to energize one of said lights when amagnetic field being sensed does not exceed a predetermined normalintensity and to energize the other of said lights when a magnetic fieldbeing sensed does exceed said predetermined normal intensity.

9. A detection device in accordance with claim 6, wherein the signalingmeans also includes an audible alarm.

10. A detection device in accordance with claim 1, wherein the carriageincludes a handle for manual manipulation of said carriage.

11. A detection device in accordance with claim 1, wherein the signalingmeans in the control circuitry includes a signaling means indicative ofnormal magnetic field intensity and a signaling means indicative ofabnormal field intensity, and wherein the control circuitry is arrangedto actuate the normal signaling means during a predetermined range ofmagnetic field intensity to which the sensing means is exposed and toactuate the abnormal signaling means when said range of magnetic fieldintensity is exceeded.

12. A detection device in accordance with claim 11, wherein the controlcircuitry includes means for adjusting the range of magnetic fieldintensity regarded as normal at any given time.

1. A detection device for indicating short circuits in electrolyticcells, comprising a carriage having a running surface adapted to seatupon and travel across a series of electrode suspension bars conductingelectrical current to electrode pairs in an electrolytic cell; a sensingunit responsive to steady magnetic fields surrounding the respectivesuspension bars as produced by direct current flow through saidsuspension bars, said sensing unit being secured in said carriage at afixed level above said running surface thereof; and electrical controlcircuitry with which said sensing unit is electrically connected, saidcircuitry including signaling means and calibrating means and beingarranged to actuate said signaling means when the intensity of magneticfield to which said sensing unit is exposed exceeds a predeterminedlevel established by said calibrating means.
 2. A detection device inaccordance with claim 1, wherein the carriage is of sled runnerformation.
 3. A detection device in accordance with claim 1, wherein thesensing unit is a magnetodiode.
 4. A detection device in accordance withclaim 3, wherein flux concentrator means are associated with themagnetodiode.
 5. A detection device in accordance with claim 4, whereinthe flux concentrator means comprise a pair of flux concentrators atopposite sides, respectively, of the magnetodiode, each tapering towardthe magnetodiode.
 6. A detection device in accordance with claim 1,wherein the sensing unit comprises reed relay means.
 7. A detectiondevice in accordance with claim 6, wherein there are at least two reedrelays, the control circuitry, including respective resistances arrangedto bias said relays so they will be actuated at respective predeterminedlevels of magnetic field intensity.
 8. A detection device in accordancewith claim 1, wherein the signaling means includes a set of two electriclights mounted on the carriage, and the control circuitry is arranged toenergize one of said lights when a magnetic field being sensed does notexceed a predetermined normal intensity and to energize the other ofsaid lights when a magnetic field being sensed does exceed saidpredetermined normal intensity.
 9. A detection device in accordance withclaim 6, wherein the signaling means also includes an audible alarm. 10.A detection device in accordance with claim 1, wherein the carriageincludes a handle for manual manipulation of said carriage.
 11. Adetection device in accordance with claim 1, wherein the signaling meansin the control circuitry includes a signaling means indicative of normalmagnetic field intensity and a signaling means indicative of abnormalfield intensity, and wherein the control circuitry is arranged toactuate the normal signaling means during a predetermined range ofmagnetic field intensity to which the sensing means is exposed and toactuate the abnormal signaling means when said range of magnetic fieldintensity is exceeded.
 12. A detection device in accordance with claim11, wherein the control circuitry includes means for adjusting the rangeof magnetic field intensity regarded as normal at any given time.